2000-2019 年腰痛随机对照试验中的盲法、假手术和治疗效果：综述和荟萃分析方法。
Blinding, sham, and treatment effects in randomized controlled trials for back pain in 2000-2019: A review and meta-analytic approach.
机构信息
Department of Pain Management, Summit Medical Group, Berkeley Heights, NJ, USA.
Departments of Physiatry and Orthopedic Surgery, Hospital for Special Surgery, New York, NY, USA.
出版信息
Clin Trials. 2021 Jun;18(3):361-370. doi: 10.1177/1740774520984870. Epub 2021 Jan 21.
BACKGROUND
Blinding aims to minimize biases from what participants and investigators know or believe. Randomized controlled trials, despite being the gold standard to evaluate treatment effect, do not generally assess the success of blinding. We investigated the extent of blinding in back pain trials and the associations between participant guesses and treatment effects.
METHODS
We did a review with PubMed/OvidMedline, 2000-2019. Eligibility criteria were back pain trials with data available on treatment effect and participants' guess of treatment. For blinding, blinding index was used as chance-corrected measure of excessive correct guess (0 for random guess). For treatment effects, within- or between-arm effect sizes were used. Analyses of investigators' guess/blinding or by treatment modality were performed exploratorily.
RESULTS
Forty trials (3899 participants) were included. Active and sham treatment groups had mean blinding index of 0.26 (95% confidence interval: 0.12, 0.41) and 0.01 (-0.11, 0.14), respectively, meaning 26% of participants in active treatment believed they received active treatment, whereas only 1% in sham believed they received sham treatment, beyond chance, that is, random guess. A greater belief of receiving active treatment was associated with a larger within-arm effect size in both arms, and ideal blinding (namely, "random guess," and "wishful thinking" that signifies both groups believing they received active treatment) showed smaller effect sizes, with correlation of effect size and summary blinding indexes of 0.35 ( = 0.028) for between-arm comparison. We observed uniformly large sham treatment effects for all modalities, and larger correlation for investigator's (un)blinding, 0.53 ( = 0.046).
CONCLUSION
Participants in active treatments in back pain trials guessed treatment identity more correctly, while those in sham treatments tended to display successful blinding. Excessive correct guesses (that could reflect weaker blinding and/or noticeable effects) by participants and investigators demonstrated larger effect sizes. Blinding and sham treatment effects on back pain need due consideration in individual trials and meta-analyses.
背景
盲法旨在使参与者和研究者的所知或所信对研究结果的偏倚最小化。随机对照试验虽然是评估治疗效果的金标准，但通常并不评估盲法的成功程度。我们调查了腰痛试验中盲法的实施程度以及参与者猜测与治疗效果之间的关系。
方法
我们在 PubMed/OvidMedline 上进行了一项综述，检索时间为 2000 年至 2019 年。入选标准为提供治疗效果数据且有参与者猜测治疗分组数据的腰痛试验。对于盲法，使用盲法指数作为过度正确猜测的机会校正测量值（随机猜测为 0）。对于治疗效果，使用组内或组间效应量。对研究者猜测/盲法或治疗方式进行了探索性分析。
结果
共纳入 40 项试验（3899 名参与者）。活性治疗组和假治疗组的平均盲法指数分别为 0.26（95%置信区间：0.12，0.41）和 0.01（-0.11，0.14），这意味着活性治疗组中 26%的参与者认为他们接受了活性治疗，而假治疗组中只有 1%的参与者认为他们接受了假治疗，超出了随机猜测的可能性。更大的接受活性治疗的信念与两组内的更大的组内效应量相关，而理想的盲法（即“随机猜测”和“一厢情愿的想法”，表示两组都认为他们接受了活性治疗）则显示出更小的效应量，效应量与汇总盲法指数之间的相关性为 0.35（ = 0.028），用于组间比较。我们观察到所有治疗方式的假治疗效果都非常大，而研究者的（不）盲法相关性更大，为 0.53（ = 0.046）。
结论
腰痛试验中接受活性治疗的参与者更正确地猜测了治疗分组，而接受假治疗的参与者往往表现出成功的盲法。参与者和研究者的过度正确猜测（可能反映了较弱的盲法和/或明显的效果）显示出更大的效应量。在个体试验和荟萃分析中，需要充分考虑盲法和假治疗对腰痛的影响。
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